Block out of square

Some of yall are makin this WAY more complex than "it is". Check the crank bore against the cam bore. If it's good, machine the bellhousing flat. If the crank bore isn't parallel with the cam bore, line bore it so it is. Then check the bellhousing. If it's out, plane it flat. Problem solved.

Since none of the "modern" line bore machines set up off the bellhousing pattern, it's a moot point as far as a machining reference.